CMake 3.0.0 warnings

[Samuel Jackson]

I tried building Mantid with CMake 3.0.0. It worked great, but I get a bunch of warnings that look something like the following:

CMake Warning (dev) in MantidQt/Python/CMakeLists.txt:
  Policy CMP0043 is not set: Ignore COMPILE_DEFINITIONS_<Config> properties.
  Run "cmake --help-policy CMP0043" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

Here's what the CMake docs say about CMP0043: ​http://www.cmake.org/cmake/help/v3.0/policy/CMP0043.html

Probably not the most high priority ticket, but we will most likely have to deal with it sooner or later.

[Federico Montesino Pouzols]

User newer compiler defs syntax in cmake when possible, re #9833

Changeset: 9f26a4fa06437e4cb2e79047624dd7a8792bccf9

[Federico M Pouzols]

To test: build Mantid with a recent cmake (>3) and double-check that the annoying warnings are not shown anymore. This has been in the develop branch for a while, so I'd assume there's no bad surprises with this ticket.

If you happen to have an old cmake (<=2.8.9) at hand you can also test that it all builds fine. Some of the build machines do actually have such old cmakes and they have been happily building without any issues.

---

This is in principle simple to fix, provided that everybody had cmake >= 2.8.10 (​http://www.cmake.org/cmake/help/v3.0/policy/CMP0043.html).

However, in the build servers it seems we still have an old cmake:

rhel6-build: cmake 2.8.9

(at least I've seen it in one of the Jenkins logs, then I've also seen 2.10.2)

The other systems would be ready for the new compile definitions style:

osx-10.8: cmake 2.8.12.2 / 2.8.11.2

ubuntu-14.04: cmake 2.8.12.2

win7: cmake 2.8.10.2

So I put the new style commands inside an if VERSION_GREATER, it should be safe for old cmakes out there. For me it's working fine in both debug and release builds, and it seems not to break the develop builds.

[Steven Hahn]

Merge remote-tracking branch 'origin/bugfix/9833_cmake_deprecated_compile_definitions_warning'

Full changeset: ​9a87be8475e37a71562dbd38e798c2522c3b01af

[Stuart Campbell]

This ticket has been transferred to github issue ​10675